How can I create an HttpListener class on a random port in C#?

TcpListener will find a random un-used port to listen on if you bind to port 0.

public static int GetRandomUnusedPort()
{
    var listener = new TcpListener(IPAddress.Any, 0);
    listener.Start();
    var port = ((IPEndPoint)listener.LocalEndpoint).Port;
    listener.Stop();
    return port;
}